THE AQUARIUM. 



415 



them within the reservoir. This sup- 

 ply would be sufficient to make up for 

 the loss sustained by evaporation and 



Fig. 569. 



leakage, as well as to secure constant 

 change of the water, to prevent it from 

 becoming stagnant and unwholesome, the 

 highest point of level being provided with 

 a waste or overflow pipe. In this centre 

 cistern, being the highest part of the 

 house, the taller species of aquatics are 

 to be grown. We have thought it unne- 

 cessary to show the hot-water pipes in 

 the centre tank a, or passage round it, as 

 they are shown so clearly in the section, 

 fig. 568. We may remark that all these 

 pipes, being laid in a circular direction, 

 should be 21-inch leaden pipes, by which 

 means few j oints will be required. The side 

 tanks b b are to be appropriated to the cul- 

 tivation of the lower-growing and floating 

 kinds. These latter tanks should be divided 

 by partitions, so that various depths of 

 water can be secured to suit the different 

 habits of the plants, and one division 

 should be set apart for bog plants, or such 

 as merely require a damp surface, as the 

 genera Sarracenia, Drosera, &c. The 



floors and sides of the passages should 

 be laid with polished Bangor slate, Caith- 

 ness pavement, Minton's patent tiles, 

 or covered with patent 

 Antonica, in imitation 

 of polished Aberdeen 

 granite, or any of the 

 various coloured mar- 

 bles, which can all be 

 imitated to the great- 

 est perfection by this 

 excellentmaterial,and 

 at littlemore cost than 

 that of Roman cement. 

 The tops and inner 

 sides of the tanks, as 

 far as they are not 

 covered with water, 

 may be covered with 

 the same material. 



In regard to heat- 

 ing, hot-water pipes 

 should be laid in the 

 bottom of each tank, 

 as shown at c c c c c c 

 in ground plan, and 

 atmospheric heat ob- 

 tained by the same 

 means, the pipes being 

 laid under the foot- 

 paths in chambers dis- 

 connected from the 

 side walls, to prevent 

 the abstraction of heat ; in fact, they should 

 be placed in what may be called a well- 

 built flue without covers. To admit this 

 heat into the body of the house, an elegant 

 pattern of brass grating should be laid in 

 the floor, flush with the surface, and 

 directly above the pipes, so that perpen- 

 dicular radiation may not be obstructed. 

 Should Minton's tiles be used— and they 

 are, of all other floors, not only the most 

 elegant, but also the most durable— a diffe- 

 rent mode of admitting the heat may be 

 adopted — namely, by plain, square, cir- 

 cular, or angular brass ventilators, cut to 

 the same pattern with the figures on the 

 tiles, which should be introduced at least 

 every 3 feet. The principal objection 

 to placing flues or hot-water pipes under 

 the floors of hothouses, is, that provision 

 is not made for preventing the heat being 

 absorbed by the surrounding walls, soil, 

 &c, and also that no supply of fresh air 

 is admitted to cause a circulation and 

 drive the heat upwards. Air in a state 



